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1.
BMC Genomics ; 18(1): 511, 2017 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-28676104

RESUMO

BACKGROUND: Efforts to resolve the transcribed sequences in the equine genome have focused on protein-coding RNA. The transcription of the intergenic regions, although detected via total RNA sequencing (RNA-seq), has yet to be characterized in the horse. The most recent equine transcriptome based on RNA-seq from several tissues was a prime opportunity to obtain a concurrent long non-coding RNA (lncRNA) database. RESULTS: This lncRNA database has a breadth of eight tissues and a depth of over 20 million reads for select tissues, providing the deepest and most expansive equine lncRNA database. Utilizing the intergenic reads and three categories of novel genes from a previously published equine transcriptome pipeline, we better describe these groups by annotating the lncRNA candidates. These lncRNA candidates were filtered using an approach adapted from human lncRNA annotation, which removes transcripts based on size, expression, protein-coding capability and distance to the start or stop of annotated protein-coding transcripts. CONCLUSION: Our equine lncRNA database has 20,800 transcripts that demonstrate characteristics unique to lncRNA including low expression, low exon diversity and low levels of sequence conservation. These candidate lncRNA will serve as a baseline lncRNA annotation and begin to describe the RNA-seq reads assigned to the intergenic space in the horse.


Assuntos
Cavalos/metabolismo , RNA Longo não Codificante/genética , Transcriptoma , Animais , Bases de Dados Genéticas , Perfilação da Expressão Gênica , Cavalos/genética , Especificidade de Órgãos , Análise de Sequência de RNA
2.
BMC Genomics ; 18(1): 103, 2017 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-28107812

RESUMO

BACKGROUND: Transcriptome interpretation relies on a good-quality reference transcriptome for accurate quantification of gene expression as well as functional analysis of genetic variants. The current annotation of the horse genome lacks the specificity and sensitivity necessary to assess gene expression especially at the isoform level, and suffers from insufficient annotation of untranslated regions (UTR) usage. We built an annotation pipeline for horse and used it to integrate 1.9 billion reads from multiple RNA-seq data sets into a new refined transcriptome. RESULTS: This equine transcriptome integrates eight different tissues from 59 individuals and improves gene structure and isoform resolution, while providing considerable tissue-specific information. We utilized four levels of transcript filtration in our pipeline, aimed at producing several transcriptome versions that are suitable for different downstream analyses. Our most refined transcriptome includes 36,876 genes and 76,125 isoforms, with 6474 candidate transcriptional loci novel to the equine transcriptome. CONCLUSIONS: We have employed a variety of descriptive statistics and figures that demonstrate the quality and content of the transcriptome. The equine transcriptomes that are provided by this pipeline show the best tissue-specific resolution of any equine transcriptome to date and are flexible for several downstream analyses. We encourage the integration of further equine transcriptomes with our annotation pipeline to continue and improve the equine transcriptome.


Assuntos
Perfilação da Expressão Gênica , Genoma , Genômica , Transcriptoma , Animais , Mapeamento Cromossômico , Análise por Conglomerados , Biologia Computacional/métodos , Genômica/métodos , Sequenciamento de Nucleotídeos em Larga Escala , Cavalos , Anotação de Sequência Molecular , Especificidade de Órgãos/genética , Isoformas de RNA
3.
Cerebellum ; 16(2): 462-472, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-27709457

RESUMO

Equine cerebellar abiotrophy (CA) is a hereditary neurodegenerative disease that affects the Purkinje neurons of the cerebellum and causes ataxia in Arabian foals. Signs of CA are typically first recognized either at birth to any time up to 6 months of age. CA is inherited as an autosomal recessive trait and is associated with a single nucleotide polymorphism (SNP) on equine chromosome 2 (13074277G>A), located in the fourth exon of TOE1 and in proximity to MUTYH on the antisense strand. We hypothesize that unraveling the functional consequences of the CA SNP using RNA-seq will elucidate the molecular pathways underlying the CA phenotype. RNA-seq (100 bp PE strand-specific) was performed in cerebellar tissue from four CA-affected and five age-matched unaffected horses. Three pipelines for differential gene expression (DE) analysis were used (Tophat2/Cuffdiff2, Kallisto/EdgeR, and Kallisto/Sleuth) with 151 significant DE genes identified by all three pipelines in CA-affected horses. TOE1 (Log2(foldchange) = 0.92, p = 0.66) and MUTYH (Log2(foldchange) = 1.13, p = 0.66) were not differentially expressed. Among the major pathways that were differentially expressed, genes associated with calcium homeostasis and specifically expressed in Purkinje neurons, CALB1 (Log2(foldchange) = -1.7, p < 0.01) and CA8 (Log2(foldchange) = -0.97, p < 0.01), were significantly down-regulated, confirming loss of Purkinje neurons. There was also a significant up-regulation of markers for microglial phagocytosis, TYROBP (Log2(foldchange) = 1.99, p < 0.01) and TREM2 (Log2(foldchange) = 2.02, p < 0.01). These findings reaffirm a loss of Purkinje neurons in CA-affected horses along with a potential secondary loss of granular neurons and activation of microglial cells.


Assuntos
Cerebelo/metabolismo , Transtornos Heredodegenerativos do Sistema Nervoso/veterinária , Doenças dos Cavalos/genética , Transcriptoma , Animais , Cerebelo/crescimento & desenvolvimento , Análise por Conglomerados , DNA Glicosilases/genética , DNA Glicosilases/metabolismo , Feminino , Expressão Gênica , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Transtornos Heredodegenerativos do Sistema Nervoso/metabolismo , Doenças dos Cavalos/metabolismo , Cavalos , Masculino , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Aprendizado de Máquina não Supervisionado
4.
Transgenic Res ; 25(3): 329-43, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-26820414

RESUMO

The recombinant production of therapeutic proteins for human diseases is currently the largest source of innovation in the pharmaceutical industry. The market growth has been the driving force on efforts for the development of new therapeutic proteins, in which transgenesis emerges as key component. The use of the transgenic animal platform offers attractive possibilities, residing on the low production costs allied to high productivity and quality of the recombinant proteins. Although many strategies have evolved over the past decades for the generation of transgenic founders, transgenesis in livestock animals generally faces some challenges, mainly due to random transgene integration and control over transgene copy number. But new developments in gene editing with CRISPR/Cas system promises to revolutionize the field for its simplicity and high efficiency. In addition, for the final approval of any given recombinant protein for animal or human use, the production and characterization of bioreactor founders and expression patterns and functionality of the proteins are technical part of the process, which also requires regulatory and administrative decisions, with a large emphasis on biosafety. The approval of two mammary gland-derived recombinant proteins for commercial and clinical use has boosted the interest for more efficient, safer and economic ways to generate transgenic founders to meet the increasing demand for biomedical proteins worldwide.


Assuntos
Animais Geneticamente Modificados/genética , Biofarmácia/tendências , Gado/genética , Proteínas Recombinantes/genética , Animais , Reatores Biológicos , Técnicas de Transferência de Genes/tendências , Humanos , Proteínas Recombinantes/biossíntese
6.
Reprod Domest Anim ; 49(4): 648-656, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24943879

RESUMO

The presence of the zona pellucida has been perceived as a requirement for the oviductal transfer of cloned embryos at early stages of development while protecting the embryo from an immune system response. We hypothesized that steroid hormone therapy could reduce a potential cellular immune response after the transfer of zona-free cloned embryos into the oviduct of recipient female goats. In Experiment 1, seven does were used to study the systemic immunosuppressant effect of the methylprednisolone administration (for 3 days) on blood cell counts. Whole blood was collected prior to treatment with methyprednisolone and then on Days 1, 2, 3, 4, 7, 14, 21 and 28 after the first dose of methylprednisolone for the analysis of haematological parameters. Methylprednisolone treatment significantly reduced circulating white blood cells and neutrophils in comparison with pre-treatment levels, demonstrating a systemic immunosuppressant effect. In Experiment 2, a group of 58 does were used as recipient females to study the effect of administration of methylprednisolone for 3 days on the establishment of pregnancies after the transfer of zona-free cloned embryos into the oviducts. No effects on pregnancy rates on Day 30 were observed regarding the distinct treatment groups (control vs. methylprednisolone), the source of oocytes (in vivo- vs in vitro-matured) or the presence or absence of the zona pellucida in embryos. In summary, methylprednisolone was effective at inducing a systemic immunosuppressed state in goats, but the treatment prior to embryo transfer did not affect pregnancy rates. Moreover, pregnancy rates were similar between zona-free and zona-intact goat cloned embryos.


Assuntos
Clonagem de Organismos/veterinária , Transferência Embrionária/veterinária , Cabras , Terapia de Imunossupressão/veterinária , Metilprednisolona/administração & dosagem , Animais , Transferência Embrionária/métodos , Feminino , Terapia de Imunossupressão/métodos , Contagem de Leucócitos/veterinária , Neutrófilos , Técnicas de Transferência Nuclear/veterinária , Gravidez , Taxa de Gravidez , Zona Pelúcida/imunologia
7.
J Dairy Sci ; 95(12): 7200-5, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23040022

RESUMO

Coagulase-negative staphylococci (CNS) are the most commonly isolated bacteria from goat milk, but they have often been identified with phenotypic methods, which may have resulted in misclassification. The aims of this paper were to assess the amount of misclassification of a phenotypic test for identifying CNS species from goat milk compared with transfer RNA intergenic spacer PCR (tDNA-PCR) followed by capillary electrophoresis, and to apply the tDNA-PCR technique on different capillary electrophoresis equipment. Milk samples were collected from 416 does in 5 Californian dairy goat herds on 3 occasions during lactation. In total, 219 CNS isolates were identified at the species level with tDNA-PCR and subjected to the API 20 Staph identification test kit (API Staph; bioMérieux, Durham, NC). If the same species was isolated multiple times from the same udder gland, only the first isolate was used for further analyses, resulting in 115 unique CNS isolates. According to the tDNA-PCR test, the most prevalent CNS species were Staphylococcus epidermidis, Staphylococcus caprae, and Staphylococcus simulans. Typeability with API staph was low (72%). Although the API Staph test was capable of identifying the majority of Staph. epidermidis and Staph. caprae isolates, sensitivity for identification of Staph. simulans was low. The true positive fraction was high for the 3 most prevalent species. It was concluded that the overall performance of API Staph in differentiating CNS species from goat milk was moderate to low, mainly because of the low typeability, and that genotypic methods such as tDNA-PCR are preferred.


Assuntos
Leite/microbiologia , Staphylococcus/genética , Animais , Eletroforese Capilar/métodos , Eletroforese Capilar/veterinária , Feminino , Cabras/microbiologia , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da Polimerase/veterinária , RNA Bacteriano/genética , RNA de Transferência/genética , Staphylococcus/classificação , Staphylococcus epidermidis/genética
8.
Pathology ; 54(1): 49-54, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34955242

RESUMO

Previous reports have shown that quantification of high tumour grade is of prognostic significance for patients with prostate cancer. In particular, percent Gleason pattern 4 (GP4) has been shown to predict outcome in several studies, although conflicting results have also been reported. A major issue with these studies is that they rely on surrogate markers of outcome rather than patient survival. We have investigated the prognostic predictive value of quantifying GP4 in a series of prostatic biopsies containing Gleason score 3+4=7 and 4+3=7 tumours. It was found that the length of GP4 tumour determined from the measurement of all biopsy cores from a single patient, percent GP4 present and absolute GP4 were all significantly associated with distant progression of tumour, all-cause mortality and cancer-specific mortality over a 10-year follow-up period. Assessment of the relative prognostic significance showed that these parameters outperformed division of cases according to Gleason score (3+4=7 versus 4+3=7). International Society of Urological Pathology (ISUP) Grade Groups currently divide these tumours, according to Gleason grading guidelines, into grade 2 (3+4=7) and grade 3 (4+3=7). Our results indicate that this simple classification results in the loss of important prognostic information. In view of this we would recommend that ISUP Grade Groups 2 and 3 be amalgamated as grade 2 tumour with the percentage of GP4 carcinoma being appended to the final grade, e.g., 3+4=7 carcinoma with 40% pattern 4 tumour would be classified as ISUP Grade Group 2 (40%).


Assuntos
Adenocarcinoma/patologia , Prognóstico , Neoplasias da Próstata/patologia , Biópsia com Agulha de Grande Calibre , Humanos , Masculino , Gradação de Tumores/métodos , Próstata/patologia , Prostatectomia , Estudos Retrospectivos
9.
Sci Rep ; 9(1): 13907, 2019 09 25.
Artigo em Inglês | MEDLINE | ID: mdl-31554862

RESUMO

Primary infection of legumes by rhizobia involves the controlled localized enzymatic breakdown of cell walls at root hair tips. Previous studies determined the role of rhizobial CelC2 cellulase in different steps of the symbiotic interaction Rhizobium leguminosarum-Trifolium repens. Recent findings also showed that CelC2 influences early signalling events in the Ensifer meliloti-Medicago truncatula interaction. Here, we have monitored the root hair phenotypes of two legume plants, T. repens and M. sativa, upon inoculation with strains of their cognate and non-cognate rhizobial species, R. leguminosarum bv trifolii and E. meliloti, (over)expressing the CelC2 coding gene, celC. Regardless of the host, CelC2 specifically elicited 'hole-on-the-tip' events (Hot phenotype) in the root hair apex, consistent with the role of this endoglucanase in eroding the noncrystalline cellulose found in polarly growing cell walls. Overproduction of CelC2 also increased root hair tip redirections (RaT phenotype) events in both cognate and non-cognate hosts. Interestingly, heterologous celC expression also induced non-canonical alterations in ROS (Reactive Oxygen Species) homeostasis at root hair tips of Trifolium and Medicago. These results suggest the concurrence of shared unspecific and host-related plant responses to CelC2 during early steps of symbiotic rhizobial infection. Our data thus identify CelC2 cellulase as an important determinant of events underlying early infection of the legume host by rhizobia.


Assuntos
Celulase/metabolismo , Fabaceae/metabolismo , Fabaceae/microbiologia , Interações Hospedeiro-Patógeno/fisiologia , Rhizobium leguminosarum/metabolismo , Simbiose/fisiologia , Parede Celular/metabolismo , Parede Celular/microbiologia , Infecções por Bactérias Gram-Negativas/microbiologia , Medicago truncatula/metabolismo , Medicago truncatula/microbiologia , Fenótipo , Raízes de Plantas/metabolismo , Raízes de Plantas/microbiologia , Nódulos Radiculares de Plantas/metabolismo , Nódulos Radiculares de Plantas/microbiologia , Trifolium/metabolismo , Trifolium/microbiologia
10.
Brain Res ; 1678: 330-336, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29103988

RESUMO

Cerebellar Abiotrophy (CA) is a neurodegenerative disease in Arabian horses affecting the cerebellum, more specifically the Purkinje neurons. Although CA occurs in several domestic species, CA in Arabian horses is unique in that a single nucleotide polymorphism (SNP) has been associated with the disease. Total RNA sequencing (RNA-seq) was performed on CA-affected horses to address the molecular mechanism underlying the disease. This research expands upon the RNA-seq work by measuring the impact of the CA-associated SNP on the candidate gene MutY homolog (MUTYH) and its regulation, isoform-specific expression and protein localization. We hypothesized that the CA-associated SNP compromises the promoter region of MUTYH, leading to differential expression of its isoforms. Our research demonstrates that the CA-associated SNP introduces a new binding site for a novel transcription factor (Myelin Transcription Factor-1 Like protein, MYT1L). In addition, CA-affected horses show differential expression of a specific isoform of MUTYH as well as different localization in the Purkinje and granular neurons of the cerebellum.


Assuntos
Doenças Cerebelares/genética , Doenças Cerebelares/veterinária , Cerebelo/patologia , DNA Glicosilases/genética , Polimorfismo de Nucleotídeo Único/genética , Animais , Doenças Cerebelares/patologia , Análise Mutacional de DNA , Transtornos Heredodegenerativos do Sistema Nervoso/genética , Transtornos Heredodegenerativos do Sistema Nervoso/veterinária , Cavalos/genética , Células de Purkinje/metabolismo , Células de Purkinje/patologia
11.
Mol Cell Biol ; 9(12): 5473-9, 1989 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-2479830

RESUMO

Transgenic mice containing a sheep metallothionein 1a-sheep growth hormone fusion gene exhibited low, tissue-specific basal levels of transgene mRNA expression, resulting in slightly elevated levels of circulating growth hormone that did not lead to a detectable increase in growth. After zinc stimulation, high levels of transgene mRNA expression were induced in a number of tissues; these levels correlated with increased levels of circulating growth hormone, resulting in growth increases of up to 1.5 times the levels of controls and unstimulated transgenic mice. After removal of the zinc stimulus, transgene expression and circulating growth hormone concentrations returned to basal levels. Additional evidence from the pattern of developmental expression of the transgene suggests that zinc is the main regulator of this promoter in mice. The demonstrated regulation and low basal level of expression of the sheep metallothionein 1a promoter make it a candidate for use in other mouse transgenic studies and for use in transgenic livestock, in which regulation of expression is essential.


Assuntos
Regulação da Expressão Gênica , Genes , Hormônio do Crescimento/genética , Metalotioneína/genética , Camundongos Transgênicos/crescimento & desenvolvimento , Animais , Northern Blotting , Feminino , Genes/efeitos dos fármacos , Hormônio do Crescimento/biossíntese , Hormônio do Crescimento/sangue , Masculino , Metalotioneína/biossíntese , Camundongos , RNA/genética , RNA/isolamento & purificação , RNA Mensageiro/análise , Proteínas Recombinantes de Fusão/biossíntese , Mapeamento por Restrição , Ovinos , Transcrição Gênica , Zinco/farmacologia
12.
J Dairy Sci ; 89(2): 518-24, 2006 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-16428620

RESUMO

The potential for applying biotechnology to benefit animal agriculture and food production has long been speculated. The addition of human milk components with intrinsic antimicrobial activity and positive charge to livestock milk by genetic engineering has the potential to benefit animal health, as well as food safety and production. We generated one line of transgenic goats as a model for the dairy cow designed to express human lysozyme in the mammary gland. Here we report the characterization of the milk from 5 transgenic females of this line expressing human lysozyme in their milk at 270 microg/mL or 68% of the level found in human milk. Milk from transgenic animals had a lower somatic cell count, but the overall component composition of the milk and milk production were not different from controls. Milk from transgenic animals had a shorter rennet clotting time and increased curd strength. Milk of such nature may be of benefit to the producer by influencing udder health and milk processing.


Assuntos
Animais Geneticamente Modificados/genética , Cabras/genética , Lactação , Glândulas Mamárias Animais/enzimologia , Leite/química , Muramidase/genética , Animais , Animais Geneticamente Modificados/fisiologia , Anti-Infecciosos , Contagem de Células , Quimosina/metabolismo , Feminino , Manipulação de Alimentos/métodos , Expressão Gênica , Cabras/fisiologia , Humanos , Leite/citologia
13.
Genetics ; 143(4): 1753-60, 1996 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-8844161

RESUMO

Transgenic mice possessing an ovine growth hormone gene were used to study the effects of elevated growth hormone on quantitative genetic variation. Males hemizygous for the transgene were mated to wild-type females to produce half- and full-sib families in which approximately half the progeny were transgenic and half were wild type. Analyses of body weights at 3-10 weeks, and weight gains from 3 to 6, and 6 to 10 weeks produced estimates of the proportion of total variance due to additive genetic effects (h2) and common litter effects (c2), and the genetic correlation between transgenic and wild-type expression of each trait. At 10 weeks, body weight of transgenics exceeded that of wild types by 26 and 49% in males and females, respectively. Estimated genetic variances in the transgenic group were significantly greater than zero for body weights at most ages and for both measurements of gain. Common litter effects accounted for a similar proportion of variation in the wild-type and transgenic groups. Additive genetic correlations between wild-type and transgenic expression of body weights tended to decline with age, indicating that a partially different array of genes may have begun to affect body weight in the transgenic group.


Assuntos
Peso Corporal/genética , Hormônio do Crescimento/genética , Aumento de Peso/genética , Fatores Etários , Animais , Peso Corporal/fisiologia , Cruzamentos Genéticos , Feminino , Variação Genética , Genótipo , Hormônio do Crescimento/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos ICR , Camundongos Transgênicos , Fenótipo , Caracteres Sexuais , Ovinos , Aumento de Peso/fisiologia
14.
Pathology ; 47(6): 520-5, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26325671

RESUMO

In 2014 a consensus conference convened by the International Society of Urological Pathology (ISUP) adopted amendments to the criteria for Gleason grading and scoring (GS) for prostatic adenocarcinoma. The meeting defined a modified grading system based on 5 grading categories (grade 1, GS 3+3; grade 2, GS 3+4; grade 3, GS 4+3; grade 4, GS 8; grade 5, GS 9-10). In this study we have evaluated the prognostic significance of ISUP grading in 496 patients enrolled in the TROG 03.04 RADAR Trial. There were 19 grade 1, 118 grade 2, 193 grade 3, 88 grade 4 and 79 grade 5 tumours in the series, with follow-up for a minimum of 6.5 years. On follow-up 76 patients experienced distant progression of disease, 171 prostate specific antigen (PSA) progression and 39 prostate cancer deaths. In contrast to the 2005 modified Gleason system (MGS), the hazards of the distant and PSA progression endpoints, relative to grade 2, were significantly greater for grades 3, 4 and 5 of the 2014 ISUP grading scheme. Comparison of predictive ability utilising Harrell's concordance index, showed 2014 ISUP grading to significantly out-perform 2005 MGS grading for each of the three clinical endpoints.


Assuntos
Adenocarcinoma/patologia , Gradação de Tumores , Neoplasias da Próstata/patologia , Adenocarcinoma/mortalidade , Adenocarcinoma/terapia , Adulto , Idoso , Antagonistas de Androgênios/administração & dosagem , Antineoplásicos/administração & dosagem , Biópsia com Agulha de Grande Calibre , Quimiorradioterapia/métodos , Conferências de Consenso como Assunto , Difosfonatos/administração & dosagem , Humanos , Imidazóis/administração & dosagem , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Gradação de Tumores/métodos , Gradação de Tumores/normas , Patologia Cirúrgica/normas , Modelos de Riscos Proporcionais , Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/terapia , Sociedades Médicas , Urologia/normas , Ácido Zoledrônico
15.
J Neuropathol Exp Neurol ; 56(6): 704-13, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9184661

RESUMO

This paper is a natural three-dimensional extension of a simple two-dimensional mathematical model of glioma growth and diffusion. The model was originally constructed to simulate a case of recurrent anaplastic astrocytoma treated with chemotherapy, and then modified to allow estimation of the effects of the extent of surgical resection and of variations in growth and diffusion to cover the whole range of glioma behavior. Growth is considered to be constant and exponential (analogous to continuously compounding interest) and is expressed as a decimal fraction per day; the diffusion coefficient is expressed as cm2 per day. Model predictions suggest that diffusion, practically ignored until the present, is a more important component of glioma growth than the growth rate. Even with very early diagnosis, only those tumors with a low diffusion coefficient and a rapid growth rate benefit from a wide resection. Surgical resections generally fail, just as dropping fire-fighters into the burned out center of a forest fire fails, the action being on the periphery as the tumor cells or fires spread out from the center.


Assuntos
Glioma/patologia , Astrocitoma/patologia , Divisão Celular , Difusão , Glioma/terapia , Matemática , Modelos Teóricos
16.
Cell Prolif ; 33(5): 317-29, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11063134

RESUMO

We have extended a mathematical model of gliomas based on proliferation and diffusion rates to incorporate the effects of augmented cell motility in white matter as compared to grey matter. Using a detailed mapping of the white and grey matter in the brain developed for a MRI simulator, we have been able to simulate model tumours on an anatomically accurate brain domain. Our simulations show good agreement with clinically observed tumour geometries and suggest paths of submicroscopic tumour invasion not detectable on CT or MRI images. We expect this model to give insight into microscopic and submicroscopic invasion of the human brain by glioma cells. This method gives insight in microscopic and submicroscopic invasion of the human brain by glioma cells. Additionally, the model can be useful in defining expected pathways of invasion by glioma cells and thereby identify regions of the brain on which to focus treatments.


Assuntos
Neoplasias Encefálicas/patologia , Glioma/patologia , Modelos Biológicos , Invasividade Neoplásica/patologia , Simulação por Computador , Humanos , Imageamento por Ressonância Magnética , Fibras Nervosas/patologia , Neurônios/patologia , Neurônios/ultraestrutura , Lobo Temporal/patologia
17.
Cell Prolif ; 29(6): 269-88, 1996 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-8809120

RESUMO

We have developed a mathematical model based on proliferation and infiltration of neoplastic cells that allows predictions to be made concerning the life expectancies following various extents of surgical resection of gliomas of all grades of malignancy. The key model parameters are the growth rate and the diffusion rate. These rates were initially derived from analysis of a case of recurrent anaplastic astrocytoma treated by chemotherapies. Numerical simulations allow us to estimate what would have happened to that patient if various extents of surgical resection, rather than chemotherapies, had been used. In each case, the shell of the infiltrating tumour that remains after 'gross total removal' or even a maximal excision continues to grow and regenerates the tumour mass remarkably rapidly. By developing a model that allows the growth and diffusion rates to define the distribution of cells at the time of diagnosis, and then varying these rates by about 50%, we created a hypothetical tumour patient population whose survival times show good agreement with the results recently reported by Kreth for treatments of glioblastomas. Tenfold decreases in the rates of growth and diffusion mimic the results reported by many other investigators with more slowly growing gliomas. Thus, the model quantitatively supports the ideas that (i) gliomas infiltrate so diffusely that they cannot be cured by resection alone, surgical or radiological, no matter how extensive that may be; (ii) the more extensive the resection, regardless of the degree of malignancy of the glioma, the greater the life expectancy; and (iii) measurements of the two rates, growth and diffusion, may be able to predict survival rates better than the current histological estimates of the type and grade of gliomas.


Assuntos
Glioma/patologia , Glioma/cirurgia , Modelos Biológicos , Divisão Celular/fisiologia , Humanos , Processamento de Imagem Assistida por Computador , Recidiva , Procedimentos Cirúrgicos Operatórios/métodos , Análise de Sobrevida
18.
Cell Prolif ; 28(1): 17-31, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7833383

RESUMO

During the past two decades computerized tomography (CT) and magnetic resonance imaging (MRI) have permitted the detection of tumours at much earlier stages in their development than was previously possible. In spite of this earlier diagnosis the effects of earlier and more extensive treatments have been difficult to document. This failure has led to an increasing awareness of the importance of infiltration of glioma cells into surrounding grossly normal brain tissue such that recurrence still occurs. In this paper a simple mathematical model for the proliferation and infiltration of such tumours is introduced, based in part on quantitative image analysis of histological sections of a human brain glioma and especially on cross-sectional area/volume measurements of serial CT images while the patient was undergoing chemotherapy. The model parameters were estimated using optimization techniques to give the best fit of the simulated tumour area to the CT scan data. Numerical solution of the model on a two-dimensional domain, which took into account the geometry of the brain and its natural barriers to diffusion, was used to determine the effect of chemotherapy on the spatio-temporal growth of the tumour.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Encefálicas/radioterapia , Divisão Celular/efeitos dos fármacos , Divisão Celular/fisiologia , Divisão Celular/efeitos da radiação , Quimioterapia Adjuvante , Seguimentos , Glioblastoma/radioterapia , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Modelos Biológicos , Recidiva Local de Neoplasia/patologia , Tomografia Computadorizada por Raios X
19.
Proc Biol Sci ; 241(1300): 29-36, 1990 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-1978332

RESUMO

The spreading of cells across the surface of an epidermal wound enables epidermal migration to be studied independently of the wound contraction that occurs in deeper wounds. In particular, the stimulus for the increase in epidermal mitosis during would healing is uncertain. Our modelling suggests that biochemical regulation of mitosis is fundamental to the process, and that a single chemical with a simple regulatory effect can account for the healing of circular epidermal wounds. The model results compare well with experimental data.


Assuntos
Epiderme/fisiologia , Cicatrização , Movimento Celular , Mitose , Modelos Biológicos
20.
Proc Biol Sci ; 266(1416): 299-304, 1999 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-10081165

RESUMO

Colonies of Escherichia coli or Salmonella typhimurium form geometrically complex patterns when exposed to, or feeding on, intermediates of the tricarboxylic acid (TCA) cycle. In response to the TCA cycle intermediate, the bacteria secrete aspartate, a potent chemo-attractant. As a result, the cells form high-density aggregates arranged in striking regular patterns. The simplest are temporary spots formed in a liquid medium by both E. coli and S. typhimurium. In semi-solid medium S. typhimurium forms concentric rings arising from a low-density bacterial lawn, which are either continuous or spotted, whereas E. coli forms complex patterns arising from a dense swarm ring, including interdigitated spots (also called sunflower spirals), radial spots, radial stripes and chevrons. We present a mathematical model that captures all three of the pattern-forming processes experimentally observed in both E. coli and S. typhimurium, using a minimum of assumptions.


Assuntos
Escherichia coli/citologia , Modelos Biológicos , Salmonella typhimurium/citologia , Aderência Bacteriana/fisiologia , Quimiotaxia/fisiologia , Ciclo do Ácido Cítrico , Meios de Cultura , Escherichia coli/fisiologia , Salmonella typhimurium/fisiologia
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